1. Field of the Invention
This invention relates to apparatus for the chemical analysis of biological fluids, and more particularly to apparatus for holding and delivering fluid samples to the analysis apparatus.
2. Description of the Prior Art
In recent years, a number of automated systems have been developed for carrying out quantitative chemical analyses of fluid samples. Most of the commercially available systems utilize liquid reagents and require analyzer equipment having intricate solution handling and transport capabilities. For example, U.S. Pat. No. 3,883,308, to Matte, discloses liquid analysis apparatus in which a plurality of sample containers are carried on a circular support, a plurality of reagent cups are supported on a second circular support, and an aspirator is provided for transferring fluid from a sample container to a selected reagent cup. The bottom portions of the reagent cups are transparent to facilitate a photometric reading through the container.
As an alternative to liquid analysis systems, various essentially-dry analytical elements have been adopted for automated test procedures. Co-assigned U.S. Pat. No. 4,152, 390, granted May 1, 1979, discloses apparatus for the automatic continuous analysis of biological fluids in which a fluid sample is metered onto a test slide and is analyzed after incubation. Cups of biological fluid samples are carried on a linearly movable tray. Drops of sample fluid are dispensed onto test slides below the tray through metering tips in the bottom of each cup. The tray is incrementally advanced to align successive cups with the dispensing station.
When an entire tray has been run, it is removed and replaced with a new tray of fresh samples. During removal and replacement of a sample tray, the analysis apparatus operation is interrupted. No provision is made for substituting one or more so called STAT (a commonly used term in medical arts for immediately needed) tests without removing an entire tray.